The present invention relates to an evaporator which is suitable for use in a car air conditioner which is a refrigerating cycle mounted on, for example, an automobile.
In the present specification and appended claims, the upper and lower sides of FIGS. 1 and 2 will be referred to as “upper” and “lower,” respectively.
The present applicant has proposed an evaporator which can decrease its size and weight, can enhance its performance, and allows an expansion valve attachment member for attaching an expansion valve to be disposed near the evaporator (see Japanese Patent No. 5142109). The proposed evaporator includes a first header section having a refrigerant inlet at one end thereof; a second header section juxtaposed on the windward side of the first header section and having a refrigerant outlet at one end thereof located on the same side as the refrigerant inlet of the first header section; a third header section disposed below the first header section such that the third header section is spaced from the first header section; a fourth header section disposed below the second header section such that the fourth header section is spaced from the second header section and is juxtaposed on the windward side of the third header section; a plurality of heat exchange tubes disposed between the first header section and the third header section and between the second header section and the fourth header section such that the heat exchange tubes are spaced from one another in the longitudinal direction of the header sections and opposite end portions of the heat exchange tubes are connected to the corresponding header sections; a refrigerant inlet outlet member having a refrigerant introduction passage for feeding refrigerant into the refrigerant inlet and a refrigerant discharge passage for discharging the refrigerant from the refrigerant outlet; and an expansion valve attachment member attached to the refrigerant inlet outlet member and having a first refrigerant flow passage communicating with the refrigerant introduction passage of the refrigerant inlet outlet member and a second refrigerant flow passage communicating with the refrigerant discharge passage. The refrigerant inlet outlet member is composed of a first plate extending across and joined to the one end of the first header section and the one end of the second header section, a second plate stacked on and joined to a surface of the first plate opposite the two header sections; and a third plate stacked on and joined to a surface of the second plate opposite the first plate. At least one of the first and third plates is bulged outward, and a cutaway and a through-hole are formed in the second plate, whereby a refrigerant introduction passage and a refrigerant discharge passage are provided. One end of the refrigerant introduction passage communicates with the refrigerant inlet, the other end of the refrigerant introduction passage is opened at a vertically extending edge of the refrigerant inlet outlet member formed by the three plates. One end of the refrigerant discharge passage communicates with the refrigerant outlet, and the other end of the refrigerant discharge passage is opened at the edge of the refrigerant inlet outlet member at which the refrigerant introduction passage is opened. When the refrigerant introduction passage and the refrigerant discharge passage are viewed in a stacking direction in which all the plates are stacked, the refrigerant introduction passage and the refrigerant discharge passage intersect each other without communicating with each other. The refrigerant flowing out from the refrigerant outlet is fed to a compressor through the refrigerant discharge passage of the refrigerant inlet outlet member, one refrigerant flow passage of the expansion valve attachment member, one passage of an expansion valve attached to the expansion valve attachment member, and a pipe for establishing communication between the one passage of the expansion valve and the compressor. A portion of the refrigerant discharge passage of the refrigerant inlet outlet member, which portion is located on the downstream side in a refrigerant flow direction and has a predetermined length, is formed by outward bulged portions of the first plate and the third plate and bulging outward in the stacking direction of the three plates. The remaining portion of the refrigerant discharge passage is formed by an outward bulged portion of the third plate and bulging outward in the stacking direction of the three plates.
In the evaporator disclosed in the above-mentioned publication, in order to suppress an increase in pressure loss on the refrigerant side, at a part of the portion of the refrigerant discharge passage of the refrigerant inlet outlet member formed by the outward bulged portion of the third plate only, the internal width of the outward bulged portion is increased so as to increase the passage cross sectional area of that part. However, in the case where the thicknesses of the three plates of the refrigerant inlet outlet member are reduced to decrease the weight of the evaporator, when the internal width of a part of the outward bulged portion of the third plate is increased as described above, the strength against the pressure inside the refrigerant discharge passage may decrease.